1. Field of the Invention
The invention relates to a device for processing objects, said device being provided with a number of stations comprising supporting means for supporting objects in said stations, and with conveying means, by which the objects can be moved from one station to another station, whereby said conveying means are provided with a transport means being capable of rotating movement about a vertical axis of rotation and translating movement parallel to said axis of rotation, which transport means is fitted with gripping means for gripping and moving the objects between the various stations, and with driving means, by which said transport means can be reciprocated about its axis of rotation and be translated parallel to said axis of rotation so as to move said gripping means between said stations.
2. Description of the Prior Art
In such a device known from DE-A-37.09.354 the transport means is moved parallel to the axis of rotation by means of a piston which is movable in a cylinder. Since the axis of the cylinder coincides with the axis of rotation of the conveyor, the transport means can be tilted about a line extending transversely to the axis of rotation in a relatively simple manner. The consequence of such tilting is that the positioning accuracy of the transport means in the direction parallel to the axis of rotation is relatively small.
A device of this type is also known from U.S. Pat. No. 5,411,588. The contents of said U.S. Pat. No. 5,411,588 are considered to be incorporated herein by this reference and consequently it is not considered necessary to give a full description of the construction and operation of such a device herein.
As is set forth in said U.S. Pat. No. 5,411,588, the mechanism for reciprocating the transport means fitted with gripping means in horizontal and vertical direction comprises a cam mechanism, as well as three annular means, fitted with a wave-shaped guideway and followers cooperating therewith. In practice it has become apparent that this known construction is satisfactory per se, but that in some cases the fact that this known construction is comparatively heavy and that the various parts may take up a comparatively great amount of space in the device may constitute a drawback.
The object of the invention is to obtain a device of the above kind, which makes it possible to meet the above-described drawbacks when being used.
According to a first aspect of the invention this may be achieved in that said transport means is supported by at least three spaced-apart carriers in such manner as to be rotatable about its vertical axis of rotation, said carriers in turn being supported by sliding pieces, which are journalled in such manner as to be capable of sliding movement in vertical direction, whereby two hinged-together links are provided between a sliding piece and the frame, the first link being hinged to said sliding piece, the second link being hinged to said frame and both links being hinged to a connecting rod which is movable in a plane extending transversely to the axis of rotation, whilst said links are capable of pivoting movement between a position in which the two links include an angle with each other and a position in which the two links are at least substantially in line with said sliding piece.
This leads to a simple and compact mechanism for effecting the up-and-down movement of the transport means and the gripping means for the objects connected thereto, whereby the spaced-apart carriers provide a relatively rigid construction, which cannot be tilted.
It is noted that from GB-A-2.168.447 a device is known wherein a plate is movable in vertical direction by means of two pairs of hinged-together links. Since said links are connected to connecting rods which are movable in a plane extending parallel to the vertical direction, the number of pairs of links equals two at most. For supporting a plate or transport means firmly in one plane at least three spaced-apart supporting points are required, however. In the device according to the invention the carriers form said supporting points.
According to another aspect of the invention a crank connecting rod mechanism is connected to the transport means for reciprocating said transport means about its axis of rotation. Also this measure leads to a light and compact driving mechanism. It is preferred to connect the connecting rod to the transport means at a point located as far as possible from the axis of rotation, in order to obtain a relatively high positioning accuracy.
By using this construction a very light and simple mechanism for reciprocating the transport means can be obtained, in particular when a motor rotating in one direction, preferably an electromotor, is used for driving said crank connecting rod mechanism.